Chairs often include a seat or back. The seat or back can include a back frame or seat frame and a skin that covers the back frame or seat frame. The skins, particularly seat skins, can include a covering that covers foam attached to a liner or substrate affixed to a frame component. The foam of the skin may be welded or adhered or insert molded to the liner or substrate. The substrate or liner may then be attached to a frame component for attaching the seat skin to the frame. Screws, bolts, or other fasteners are often used to attach a frame component to a seat skin or back skin liner or substrate. U.S. Pat. Nos. 2,965,161, 3,366,991, 3,371,956, 3,556,592, 3,722,565, 4,261,667, 4,946,224, 5,011,227, 5,037,158, 5,297,851, 5,431,479, 5,464,274, 5,499,413, 5,791,733, 5,951,110, 6,019,429, 6,053,578, 6,168,239, 6,394,553, 6,349,992, 6,357,827, 6,688,692, 6,733,080, 6,817,667, 6,824,218, 6,955,402 and 7,165,811 and U.S. Patent Application Publication No. 2006/0006715 disclose examples of fasteners or fastening mechanisms used for attaching chair components together.
In some cases, it may be desirable to use a T-nut to receive fasteners used to connect a skin component to a frame component. For example, T-nuts may be used to attach wooden chair components together as disclosed in U.S. Pat. No. 3,722,565. However, the use of T-nuts often creates problems when used in conjunction with manufacturing chair components that are relatively thin, such as seat skins or back skins.
T-nuts include a body that defines an opening for receiving a fastener, such as a bolt or screw, for attaching a skin or liner to a frame. A T-nut may also include barbs that project from the body of the T-nut. The barbs are configured to attach the T-nut to a structure. For the barbs to effectively attach to the structure, the structure must have a certain thickness. The thickness of the structure can be a major limiting factor that requires increased costs for chair fabrication and can also minimize design options for certain chair structures or chair components.
If the thickness of the structure to which the T-nut or other fastener device is attached is not sufficient, then the T-nut can become displaced, loosened or separated from the structure when a fastener is inserted into the opening of the T-nut. For example, a screw that is passed through a hole in a frame component and into a threaded opening of a T-nut for attaching a skin component to a chair frame component to assemble a seat may be screwed into the opening of the T-nut. The force exerted by the screwing of the screw in the opening can cause the T-nut to rotate and become dislodged from the structure if the barbs of the T-nut are not attached to a sufficiently thick structure. Such dislodgements can prevent chair fabrication of certain chair designs.
Of course, such dislodgements may only occur intermittently during fabrication as a result of changes in structure dimensions due to tolerance control problems or may only act to loosen the T-nut from a structure. If such dislodgements go undetected during chair manufacturing, the dislodgments can create a problem for a chair purchaser. For instance, such a chair may require maintenance shortly after being purchased. Such problems can reduce the goodwill of the chair provider and can detract from the desirability of the chair.
A new method of assembling a chair is needed that can permit use of standard fastening devices such as T-nuts while also reducing manufacturing problems and providing broader design options.